"This week, Google introduced the webmaster and SEO world to a new ranking signal. Webmasters using HTTPS (HTTP over TLS, or Transport Layer Security) to make their sites more secure will be looked upon more favourably than those that don’t in Google’s search engine. That’s not to say that HTTPS trumps everything else. In fact, the company indicated that it’s a pretty weak signal, at least for now. You can expect it to grow in importance over time." - www.webpronews.com

Overall SSL (https:www....) Presently has very little impact on the overall site ranking, this may change in the future. But for the present it's likely to have very limited impact of your search results. For E commerce sites use a payment gateway it might be worst considering as site visitors are more likely to consider inputting their payment details into a site which is clearly using SSL encryption. But as all commonly used payment systems us SSL as standard visitors buying online should pay more attention at the payment stage, rather that at the selection of product stage.

So does SSL really matter as far as site rankings are concerned? No, not at the moment....